When did tv sets becamed more relaible and why?

[Alex KL-1]

Originally Posted by Electronic M

More stable mains?!? They're worse now than I remember them being as a kid. Noise, spikes/dips, outages I seen more of all the last few years than growing up.

The late 60s Zenith's with all film caps, silicone flybacks, and lytics not much different from modern ones (ignoring size) are about as you describe a hypothetical modern set, and are fairly long lived.

Hehe, spikes and noise... here sometimes a very huge spike occurs in the waveform, making noise in EMI filter, trafos, even in some motors...
And, some years ago, I worked at a transformer factory, with plenty of motor inverters: the mains waveform at that place with full production run are almost a squarewave (with rounded corners...)
Ahh, those modern appliances...

[JohnCT]

Originally Posted by zeno

IIRC the Sylvania was a D-12. The resistors went between the 250V & 24V.
Caused quite a lot of havoc.

Yep, D-12 rings a bell. I was a young shaver when those came out.

John

EDIT: These came out in the late 60s, so I was NOT shaving yet!!!

[dieseljeep]

Originally Posted by Alex KL-1

Hehe, spikes and noise... here sometimes a very huge spike occurs in the waveform, making noise in EMI filter, trafos, even in some motors...
And, some years ago, I worked at a transformer factory, with plenty of motor inverters: the mains waveform at that place with full production run are almost a squarewave (with rounded corners...)
Ahh, those modern appliances...

You have to wonder what the waveforms look like using invertors to convert HV DC to 3 phase AC, such is in use today.
Three phase AC Motors have to be a special design to be invertor duty!

[ARC Tech-109]

Originally Posted by dieseljeep

You have to wonder what the waveforms look like using invertors to convert HV DC to 3 phase AC, such is in use today.
Three phase AC Motors have to be a special design to be invertor duty!

Has to do with the way the inverter creates the sinewave, its basically a high frequency duty cycle where the "full duty" is the crest of the sinewave and the motors have to be insulated to withstand the sharp spikes. I work at a plastics injection molding plant and run a 1500-ton horizontal press that uses two 500hp inverter driven motors to drive the melt extruder screws, According to the system monitor they take an average of 650 amps at 480V when melting glass infused nylon. Overall the press (Cincinnati-Milacron) takes 2.25 megawatt to run everything... this plant has 39 presses in total the largest being 3300 tons and the smallest takes 72KW. There are a number of reactors in the incoming substation just to smooth the power so it doesn't superimpose the noise on the town feeders.
Some of the presses use a triac based PWM heat control, I've never measured or looked at the plant power but when you duty cycle a 50KW set of heaters it's going to make some noise. The electric bill is $100k/week.

[KentTeffeteller]

Originally Posted by Telecolor 3007

I guess more relaible tv sets camed out in the '70's. For 3 main reasons:
1) Imprvoing technology;
2) The Japanese wanted to show they can make better sets;
3) More tv programs - so people wanted to watch more hours without the tv having problems.

A: When Zenith color TV sets went to the hybrid chassis. And then went to ChromaColor then ChromaColor II. And the black matrix, long lived, superb CRT that made superb pictures.

B: When Sony introduced the Trinitron and it was THE set to own in 17" and smaller into 1980.

C: When Silicon transistors became common and replaced tubes. And the Japanese used them in high numbers, and technology matured.

D: When RCA went to the XL-100 chassis. Their first classic transistor, long life set. XL stood for Xtended Life.